heh? what are you talking about dude, your making my head hurt.<br /><br />Gravity and Density don't have a linear relationship, if you wanted a planet that was 5.5 times bigger then earth but with the same density, The planet would be about 166 times heavier then Earth... But it would also have a gravitational acceleration 5.5 times greater then on earth(just plug it into a= GM/r^2, pretty simple really, you just want delta M/delta r^2 to equal one so it has the same acceleration as Earth). On the other hand if you wanted the planet to have an Earth like Acceleration it would need to be 30 times more massive then the earth.<br /><br />Now, what you would need is a solid that had a density of around (Mass of hypothetical Planet)/(Volume of Hypothetical Planet)<br />(30 * mass of earth in kg)/(4/3 * pi * (5.5* radius of earth in m)^3)<br />(30 * 5.9742 × 10^24kg)/(4/3 * pi * (5.5*6373000m)^3)<br /><br />993kg/m^3<br /><br />which is about .993 g/cm^3, for comparison, the density of water is 1g/cm^3, and the density of graphite is 2.25g/cm^3<br /><br />So what that most nearly means is that No. The Material wouldn't be dense enough, of course though, if you increase the mass of the planet 2x, you COULD do it, but then gravity might end up being strong enough to keep a very very thick atmosphere, so no again. Also if your planet had 2x the mass, most likely it would end up compressing on itself which would decrease the radius and increase the gravitational acceleration at the surface.<br /><br /><br />What I wonder though is, would it be possible to live on the upper atmosphere of these planets? I mean they have all the hydrogen you could ever want to power a fusion reaction, plus probablly many more resources just floating in the air. Not to mention huge magnetic fields which could be used to also generate power. And you wouldn't have to do much to stay on the surface, since the density of the atmosphere would be so great. Kind of like Cloud City from Star Wars.